Name: ___________________________________ Date: _______________ Block: __________
Mitosis Lab: Exploring the Life of a Cell
Part 1: Onion Root Cell Simulation (The Biology Project. University of Arizona)
In this activity, you will look at onion cells in varying stages of the cell cycle and then calculate
the percentage of cells in each phase of the cell cycle.
Directions:
1. Go to http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html
(or google search “Online Onion Root Tips Simulation” and select the first link listed)
2. Read the introduction on the first page and click next
3. List the five major phases of the cell cycle and briefly describe what happens in each.
Be sure to draw a quick sketch of each phase to use for comparison later.
Phase
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Description
Sketch of Phase
Bannister, 2014
Name: ___________________________________ Date: _______________ Block: __________
Mitosis Lab: Exploring the Life of a Cell
4. When you have finished describing and sketching each phase, click next to see the table
below:
Interphase
Prophase
Metaphase
Anaphase
Telophase
Total
Number of
Cells
36
Percentage
of Cells
100%
5. Click next one more time. You will see a small (unfortunately tiny) picture of a cell in
one of the five phases of the cell cycle. Begin identifying characteristics of each picture
and then classify them into their corresponding phases by clicking the links. If you are
right, they will be placed in the correct column for you. If you are incorrect, a hint will
appear and you will need to try assigning it again.
6. Classify and assign each of the 36 cells given.
7. Next, calculate the percentage of each phase observed. (hint: just like you text scores)
# 𝑜𝑓 𝑐𝑒𝑙𝑙𝑠 𝑖𝑛 𝑖𝑛𝑡𝑒𝑟𝑝ℎ𝑎𝑠𝑒
∗ 100 = % 𝑖𝑛 𝑖𝑛𝑡𝑒𝑟𝑝ℎ𝑎𝑠𝑒
36
And repeat for prophase, metaphase, anaphase, and telophase
Part 1 Analysis:
1. Which phase did you observe most of your cells to be in? Why do you think this is so??
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Bannister, 2014
Name: ___________________________________ Date: _______________ Block: __________
Mitosis Lab: Exploring the Life of a Cell
Part 2: Mitosis Observations with the Light Microscopes
Now that you have simulated the steps of mitosis and categorized pictures of cells on the
internet, you will observe onion root tips in real life under a light microscope. Locate one cell
in each phase of the cell cycle (interphase, prophase, metaphase, anaphase, and telophase) and
draw it in the circles below. BE SURE TO label each circle with the phase you have drawn.
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Bannister, 2014
Name: ___________________________________ Date: _______________ Block: __________
Mitosis Lab: Exploring the Life of a Cell
Part 2 Analysis:
2. In your own opinion, was it easier to identify each stage of the cell cycle using the
computer simulation or by seeing them in real-life on the microscope slides?
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3. Looking in the light microscopes, did you see a similar percentage of cells in interphase
as you did using the computer simulation? Compare your findings.
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4. Would you expect to see similar percentages of cell phases in a slide containing animal
cells? Why or why not??
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